Percutaneous discectomy : a current treatment for lumbar disc herniation

Objective: Describe the functional outcomes of patients with contained lumbar disc herniation (L4-L5, L5-S1) treated with manual percutaneous nucleotomy (MPN) and demonstrate that it remains a technique with good results. Methods: A prospective, longitudinal study with 110 patients contained with lumbar disc herniation (LDH) treated with (MPN). The evaluation was pre-surgical and 4, 30, 180 and 365 days after the surgery. We used Numeric Pain Scale (NPS), Oswestry Disability Index (ODI) and Macnab criteria. Descriptive and inferential statistics for differences. Results: N=110: 58 (52.72%) men, 52 (47.27%) women; average age 37.95 years (14-56) ± 10.60; most affected level: L4-L5 in 63 (57.14%) patients. NPS preoperative average: 7.75 (5-9) ± 1.12, and at 365 days: 2.14 (0-7) ± 2.37. The mean preoperative ODI was 37% (28%-40%) + 3.06, and at 365 days 9.52% (0%-40%) + 13.92. The prognosis (ODI) was good to 79 (71.81%) patients at 365 days, regular in 26 (23.63%) and poor in 5 (4.57%), corresponding respectively to patients with no, mild, moderate and severe disability. The Macnab criteria showed similar results (p = 0.00, 95% CI 0.00 to 0.13 Student’s t). Conclusions: The results were good at one-year follow-up (p = 0.00), demonstrating that the MPN is still a good option for lumbosciatic pain relief.


INTROdUCTION
8][9] The epidemiology of low back pain is directly related to degenerative disorders of the intervertebral discs, among them herniated discs. 10The classical symptoms of a herniated lumbar disc can start with low back pain (lumbalgia) and evolve into radicular pain that we confirm clinically using the Lasègue sign 11 (sensitivity of 91% , specificity of 26%). 9reatment of this disease can be conservative (changes to daily activities, exercise, analgesics, physiatry, and rehabilitation) or surgical.Percutaneous nucleotomy is a minimally invasive disc decompression technique approved by the Food and Drug Administration (FDA) in the year 2000, 12 defining it as any discectomy procedure not requiring open dissection of the thoracolumbar fascia. 13he technique was first developed by Hijikata, 14,15 who performed percutaneous decompression and resection of the nucleus pulposus of the intervertebral disc following discography, reporting 60% to 65% satisfactory results in his case series.(Figures 1 and 2) The percutaneous nucleotomy, as a minimally invasive decompression technique, enables a reduction of pain and of the complications associated with open intervention (standard discectomy) and an earlier return to daily activities, in addition to reducing the total cost of medical treatment. 11owever, today it is not widely practiced and whether or not there is clear evidence presented about the superiority of this minimally invasive technique as compared to others is still being debated.There is a lack of high-quality studies to support it or the new techniques being devveloped. 13he objective of our study is to describe the functional outcomes of patients with contained lumbar disc hernia (L4-L5, L5-S1) treated with percutaneous manual nucleotomy (PMN) after one year of evolution and to demonstrate that it continues to be a viable technique with good results.

MATERIAL ANd METHOdS
Descriptive, longitudinal, prospective, cohort study including patients selected from the outpatient service with low back pain secondary to lumbar disc hernia of L4-L5 and L5-S1.We included those with only one level affected, with chronic lumbosciatic pain previously treated with medications and rehabilitation for more than six months without good response, and who underwent percutaneous manual nucleotomy under fluoroscopy.We excluded those patients with changes in behavior, calcified or non-contained hernias, narrow lumbar canal, spondylolisthesis, congenital deformities, and instability.Patients who wished to leave the study, who did not attend follow-up, or who underwent surgical reintervention were eliminated.All the patients were diagnosed clinically and corroborated by plain radiographs and lumbar magnetic resonance without contrast.We used a Numeric Pain Scale (NPS) to evaluate pain, the Oswestry Index (ODI) to evaluate functional disability, and the Macnab criteria for the therapeutic evaluation of the clinical results.The variables used were age, sex, symptom evolution time, complications, NPS, the Oswestry Scale, and the Macnab Criteria.In the numeric pain scale we considered zero to be without pain, 1 to 4 points as mild pain, 5 and 6 points as moderate pain, and 7 to 10 points as severe pain.For the Oswestry Disability Index, the percentage of disability was considered to be minimal from 0 to 20 points, moderate from 21 to 40 points, severe from 41 to 60 points, disability from 61 to 80 points, and exaggerated for 81 points and above.For the Macnab Criteria, results were considered to be excellent when the patient presented no pain or restriction of activity, good when there was occasional pain in the lower back or legs sufficient enough to interfere with the patient's daily life activities or their ability to enjoy leisure time, normal with improved functional capacity but with intermittent pain severe enough to limit or modify work or leisure activities, and poor when there was no improvement or the improvement was not enough to permit increased activity and a new surgical intervention may be necessary. 16he NPS and Oswestry scales were applied preoperatively to the patients who met the inclusion criteria, and then at 4, 30, 180, and 365 days following surgery and the results were noted on a data collection sheet.We used the SPSS v 22 program from IBM.For the purpose of this study, we considered the results to be good when there was a reduction of 4 points compared to the initial score, when a return to normal activities was possible, and when there were no signs of radicular compression or functional limitation (NPS of 0 to 4 and Oswestry of 0 to 20).The project was submitted to and approved by the Institutional Review Board of the Hospital Germán Díaz Lombardo (HGDL-NP001), and complies with the ethical and design aspects according to the items registered in the following: Regulations of the General Health Law.According to the regulations of the General Health Law for Research Material, for health, Titles from the first to the sixth and ninth 1987.Technical Norm no.313 for the submission of research projects and technical reports in health care institutions.Federal regulation: title 45, section 46 and what is consistent with good clinical practices.Declaration of Helsinki: ethical principles in medical research on human beings, with the latest revision in Scotland, October 2000.ethical principles originating in the World Medical Association's Declaration of Helsinki, titled, "All the subjects being studied will sign the informed consent regarding the scope of the study and the authorization for use of the data obtained in scientific presentations and publications, maintaining the anonymity of the participants".The letter of informed consent was accepted.

RESULTS
There were a total of 100 patients, 58 of whom (52.73%) were men and 52 of whom (47.27%) were women, with an average of 37.95 years of age (minimum 14 -maximum 56, SD = 10.60 years), all operated at one level.The average results of the NPS were 7.75 (minimum 5 -maximum 9), SD 1.12 prior to surgery, 2.43 (minimum 0 -maximum 7) SD 1.88 at 4 days, 2.05 (minimum 0 -maximum 7) SD 2.24 at 30 days, 2.10 (minimum 0 -maximum 7) SD at 180 days, and 2.14 (minimum 0 -maximum 7) SD 2.37 at 365 days.The differences between the NPS values measured prior to surgery and at 365 days are shown in Table 1.The average Oswestry Disability Index (ODI) was 37 (minimum 28maximum 40) SD 3.06 prior to surgery, 8.48 (minimum 0 -maximum 34) SD 11.72 at 30 days, 9.33 (minimum 0 -maximum 40) SD 13.84 at 180 days, and 9.52 (minimum 0 -maximum 40) SD 13.92 at 365 days.The differences between the ODI measured prior to surgery and at 365 days are shown in Table 2. Therapeutic effectiveness was established in our series according to the prognosis based on the ODI, which was good in 79 (71.81%) of the patients, normal in 26 (23.63%), and poor in 5 (4.57%) of the patients at 365 days following surgery.According to the Macnab criteria, 16 78 (71.4%) patients were excellent or good, 21 (19.08%) were poor, and 11 (9.52%) patients were bad at 365 days.
Mexican series in which 71.42% were women. 3However similar prospective studies, such as that of Amoretti et al., 6 note a similar distribution between the sexes (50% men, 50% women).On the contrary, Hijikata 14,15 reports a predominance of males of 60.20% in his series, which agrees with that reported in our series.Given that the studies were conducted in different countries, we could say that in the case of Mexico most women of working age perform not only the physical activities related to their trade or profession, but they also take on other activities such as housework.However, no correlation with sex has been established.In terms of the level operated, 57.14% corresponded to level L4-L5 and the remaining percentage to L5-S1 (42.86%), which is in line with the world literature that mentions that the most frequent presentation of lumbar disc hernia is in the L4-L5 and L5-S1 segments because they are the segments that are respectively the most mobile and the closest to the lumbosacral junction, the area where the greatest support of the spine is concentrated. 21n terms of the results of the NPS, an average reduction of 5.70 points was obtained at 30 days (p=0.00), of 5.65 points at 180 days (p=0.00), and of 5.61 at 365 days following surgery (p=0.00)compared with the NPS value obtained prior to surgery, showing a significant improvement in pain.It is worth mentioning that despite the fact that the lowest NPS score was recorded at 365 days, the patients had an average increase of one tenth of a point at 30 days and of one half of a point at 180 days as compared to 30 days (p=0.00).Because this increase was very small, it had no repercussions and no clinical outcome in the pain of the patients.This reduction in the NPS score coincides with the study of Aló et al. 4,5 in which they reported an improvement of 80% (p=0.001).However, Amoretti et al. 6 and Delgado et al. 3 reported an average reduction of 4 and 3.43 points, respectively.The differences in the average preoperative and preoperative NPS scores at 4, 30, 180, and 365 days were similar and statistically significant (p=0.00), as can be observed in Table 1.With respect to the Oswestry Disability Index, the average reduction in the percentage of disability was significant from the first postoperative evaluation (4 days following surgery, p=0.000) and continued until disability reached a reduction of 26 percentage points (p=0.00) at one year following surgery, as shown in Table 3, reflecting an improvement in disability from this surgical technique in patients with low back disc hernia.The difference between the preoperative and postoperative ODI (4, 30, 180, 365 days) was similar and statistically significant (p=0.00) as shown in Table 2.In our review of the literature, we found no studies that evaluated the Oswestry disability index, the numeric pain scale, or the Macnab criteria in patients who underwent mechanical percutaneous nucleotomy for lumbar disc hernia.However, other authors have used this for this type of patient, but with percutaneous nucleotomy guided by laser under fluoroscopy, endoscopy, or with dehydration of the intervertebral discs using chemical substances, making a comparison of these studies difficult.The therapeutic effectiveness of the preoperative Macnab criteria results compared to the postoperative results was good (p=0.00).We did not find any studies that included the numeric pain scale, Oswestry functional disability index, or Macnab criteria in a together in the same study in patients with low lumbar hernias treated with this technique.The success of this treatment in our series

dISCUSSION
In Mexico, intervertebral disc disease is a highly prevalent socio-economic problem. 7Percutaneous manual nucleotomy has been shown to be useful as a disc decompression technique to treat pain in patients with lumbar disc hernia, however, its use continues to be controversial 13,17 although good results in more than 70% of the cases are reported in the literature. 4,6,14,15,18,19n our study, the average age of the patients was 37.95 years, which agrees with that reported by Hijikata 14,15 and Stern 20 while in other studies by Amoretti et al. 6 and Kallas et al. 17 the average ages reported were 52 and 46 years, respectively.Another Mexican series 3 reported an average age of 59.57 years.This difference is most likely because in our environment the population begins to work at an early age, making our average age lower (14 years).
In terms of the sex of the patients who underwent intervention, 52.73% were men and 47.27% were women, as different from the probably depends on proper selection and agrees with Aló et al., 4,5 Amoretti et al., 6 and Hijikata. 14,15even though this procedure can have complications like discitis, neurological lesions, and vascular lesions, in this study there were no complications.In order to arrive at a complete, integrated evaluation of these patients, we took on the task of using the 3 evaluation scales, something that no study published in the literature has yet undertaken.

CONCLUSION
The clinical evolution of patients treated with percutaneous manual nucleotomy was good, yielding the therapeutic benefits reported in the literature.It is a minimally invasive surgical technique that should not fall into disuse given that it only requires the percutaneous nucleotomy tool and a fluoroscope to locate the anatomical landmarks.The proper selection of the patient will no doubt allow the maximum benefit to be obtained from the technique and for this reason we conclude that it continues to be a viable technique.

Figure 1 .
Figure 1.AP fluoroscopic view: A) Discography with guided needle, B) Introduction of the nucleotomy tweezers and extraction of the disc.

Table 1 .
Differences reported for the NPS.

Table 2 .
Differences reported for the ODI.